sparse-revlog: add a `trim_endidx` function in C
We are about to implement a native version of `slicechunktodensity`. For
clarity, we introduce the helper functions first.
This function implement a subpart of the python function `_trimchunk` in
`mercurial/revlogutils/deltas.py`. Handling of actual Python objects is left
to the caller function.
--- a/mercurial/cext/revlog.c Fri Nov 09 18:43:16 2018 +0100
+++ b/mercurial/cext/revlog.c Fri Nov 09 18:45:23 2018 +0100
@@ -1078,6 +1078,24 @@
return (end_offset - start_offset) + (int64_t)end_size;
}
+/* returns revs[startidx:endidx] without empty trailing revs */
+static Py_ssize_t trim_endidx(indexObject *self, const Py_ssize_t *revs,
+ Py_ssize_t startidx, Py_ssize_t endidx)
+{
+ int length;
+ while (endidx > 1 && endidx > startidx) {
+ length = index_get_length(self, revs[endidx - 1]);
+ if (length < 0) {
+ return -1;
+ }
+ if (length != 0) {
+ break;
+ }
+ endidx -= 1;
+ }
+ return endidx;
+}
+
static inline int nt_level(const char *node, Py_ssize_t level)
{
int v = node[level >> 1];